Hi all! Second writeup, and it's a simple procedure, so I'll be brief. We're all familiar with the Stealth CAI mod by BlazingCopperZX3, and this is in the same vein. I first did the Stealth mod, and then this. There was a slightly noticeable pep from the Stealth mod, and this yielded much more noticeable power gains.

This mod retains AND PERMANENTLY ALTERS your stock MAF tube. Do NOT do this mod if you plan to return to stock, unless you have a spare tube lying around.

It will only cost as much as a new air filter and possibly an 2.5" - 3" adaptor.

This is the first step - the modified MAF sensor bracket.

In order to utilize your MAF tube for this, you're going to have to reverse the sensor itself. Remove your MAF sensor, and flip it, then put it back in the slot - you'll notice both screw holes are about a quarter inch out of alignment in one direction. You need to cut into the plastic of the tube, removing as much material as you need from one side to line up the screws. I did this with my handy Craftsman Rotary tool and a universal cutter bit.

Once you get the MAF back in, run some silicone sealant around the edges, since cutting the hole will render the stock rubber grommet useless. Let it cure for a while before running it.

Here's the modified tube.

When you remove your MAF tube, it will have a metal bracket around it which bolts into your frame. Remove this, and cut the tube in half between the two plastic ribs where the bracket was. Then, using your dremel, or whatever means you have, grind down the remaining rib so all you have is a small lip, as shown. The diameter of the tube will be 2.5", and the lip will be 2.75", ensuring that you will have to slip your adaptor snugly over the lip before clamping it down. Note that the BOTTOM end of the tube (the one that used to go into your stock filter box) is now the "TOP," that is to say it will be attached to your throttle body boot. It will require no modification, you can use the existing hose clamp.

Like so!

You can use whichever filter you like. I did the APC one 'cause it was available and fit my needs. I will be fabbing a heat shield / mounting bracket for this at some time, and if the process is easy enough to write out, I'll append this how-to with the details.

To my knowledge this is exactly like a Steeda SRI. I definitely noticed an improvement in response and power.

just wondering what you did with the rubber hose coming off the air silencer box right under the little filter gage that goes to the radiator hose? didnt see this thread before i made my own thread, maybe you could check it out

Register Now

In order to be able to post messages on the Ford Focus Forum, Ford Focus ST Forum, Ford Focus RS Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:

Password

Please enter a password for your user account. Note that passwords are case-sensitive.

Password:

Confirm Password:

Email Address

Please enter a valid email address for yourself.

Email Address:

What I Drive

Year, color, and model of your car. Example: 2003 Pitch Black ZX3

Name

Your real name.

City

State

Country

Insurance

Please select your insurance company (Optional)

Log-in

User Name

Remember Me?

Password

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.